Cellular basis of abnormal calcium transients of failing human ventricular myocytes

Valentino Piacentino, Christopher R. Weber, Xiongwen Chen, Jutta Weisser-Thomas, Kenneth B. Margulies, Donald M Bers, Steven R. Houser

Research output: Contribution to journalArticlepeer-review

377 Scopus citations


Depressed contractility is a central feature of the failing human heart and has been attributed to altered [Ca2+]i. This study examined the respective roles of the L-type Ca2+ current (ICa), SR Ca2+ uptake, storage and release, Ca2+ transport via the Na+-Ca2+ exchanger (NCX), and Ca2+ buffering in the altered Ca2+ transients of failing human ventricular myocytes. Electrophysiological techniques were used to measure and control Vm and measure Im, respectively, and Fluo-3 was used to measure [Ca2+]i in myocytes from nonfailing (NF) and failing (F) human hearts. Ca2+ transients from F myocytes were significantly smaller and decayed more slowly than those from NF hearts. Ca2+ uptake rates by the SR and the amount of Ca2+ stored in the SR were significantly reduced in F myocytes. There were no significant changes in the rate of Ca2+ removal from F myocytes by the NCX, in the density of NCX current as a function of [Ca2+]i, ICa density, or cellular Ca2+ buffering. However, Ca2+ influx during the late portions of the action potential seems able to elevate [Ca2+]i in F but not in NF myocytes. A reduction in the rate of net Ca2+ uptake by the SR slows the decay of the Ca2+ transient and reduces SR Ca2+ stores. This leads to reduced SR Ca2+ release, which induces additional Ca2+ influx during the plateau phase of the action potential, further slowing the decay of the Ca2+ transient. These changes can explain the defective Ca2+ transients of the failing human ventricular myocyte.

Original languageEnglish (US)
Pages (from-to)651-658
Number of pages8
JournalCirculation Research
Issue number6
StatePublished - Apr 4 2003
Externally publishedYes


  • Congestive heart failure
  • Excitation-contraction coupling
  • Na-Ca exchanger
  • Sarcoplasmic reticulum

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine


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